// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/sha1.h"

#include <wincrypt.h>
#include <windows.h>

// This file is not being compiled at the moment (see bug 47218). If we keep
// sha1 inside base, we cannot depend on src/crypto.
// #include "crypto/scoped_capi_types.h"
#include "base/logging.h"

namespace base {

std::string SHA1HashString(const std::string& str)
{
    ScopedHCRYPTPROV provider;
    if (!CryptAcquireContext(provider.receive(), NULL, NULL, PROV_RSA_FULL,
            CRYPT_VERIFYCONTEXT)) {
        DPLOG(ERROR) << "CryptAcquireContext failed";
        return std::string(kSHA1Length, '\0');
    }

    {
        ScopedHCRYPTHASH hash;
        if (!CryptCreateHash(provider, CALG_SHA1, 0, 0, hash.receive())) {
            DPLOG(ERROR) << "CryptCreateHash failed";
            return std::string(kSHA1Length, '\0');
        }

        if (!CryptHashData(hash, reinterpret_cast<CONST BYTE*>(str.data()),
                static_cast<DWORD>(str.length()), 0)) {
            DPLOG(ERROR) << "CryptHashData failed";
            return std::string(kSHA1Length, '\0');
        }

        DWORD hash_len = 0;
        DWORD buffer_size = sizeof hash_len;
        if (!CryptGetHashParam(hash, HP_HASHSIZE,
                reinterpret_cast<unsigned char*>(&hash_len),
                &buffer_size, 0)) {
            DPLOG(ERROR) << "CryptGetHashParam(HP_HASHSIZE) failed";
            return std::string(kSHA1Length, '\0');
        }

        std::string result;
        if (!CryptGetHashParam(hash, HP_HASHVAL,
                // We need the + 1 here not because the call will write a trailing \0,
                // but so that result.length() is correctly set to |hash_len|.
                reinterpret_cast<BYTE*>(WriteInto(&result, hash_len + 1)), &hash_len,
                0)))
            {
                DPLOG(ERROR) << "CryptGetHashParam(HP_HASHVAL) failed";
                return std::string(kSHA1Length, '\0');
            }

        if (hash_len != kSHA1Length) {
            DLOG(ERROR) << "Returned hash value is wrong length: " << hash_len
                        << " should be " << kSHA1Length;
            return std::string(kSHA1Length, '\0');
        }

        return result;
    }
}

} // namespace base
